It's been shown that repeating a yoga pose, prayer, or mantra while disregarding other thoughts protects against anxiety and depression as well as physical conditions such as hypertension, cardiovascular disease, and types of cancer that are exacerbated by stress.

For the study, published in the open access journal
PLoS One, researchers at the Benson-Henry Institute for Mind/Body Medicine at Massachusetts General Hospital and Beth Israel Deaconess Medical Center Subjects trained 26 adults with no previous meditation experience for eight weeks.

At first, they were given blood tests immediately before and 15 minutes after listening to a 20-minute health education CD. This was repeated after their training, except this time with a CD that guided them through meditation. Twenty-five other individuals, who had long-term experience in evoking the relaxation response, were tested as well.

All of the subjects' blood samples revealed changes in gene expression following meditation. The changes were the exact opposite of what occurs during flight or fight. In the long-term practitioners, the effects were more pronounced and consistent.

Although the study only explored one way of reaching a relaxation response, people have been figuring this out for themselves for thousands of years, through yoga, prayer, and other forms of meditation.

This is the first time, however, that researchers have been able to show that these practices actually produce a change in gene expression.

The findings show that the effects of the relaxation response become stronger with practice, typically twice a day for 10 to 20 minutes. "Do it for years," said Benson, "and then these effects are quite powerful in how they change your gene activity."